扫描含JSON的二维码跳转后设备详情页黑屏问题求助

我用这个网站多年，第一次发帖，格式不对或者问题太基础的话见谅。现在我在扫一个带指定JSON的二维码，想通过JSON里的ZtdId把完整设备数据填充到「设备详情页」。参数能正常传到新页面，但屏幕会黑屏。

二维码中的JSON格式 #

{"Version":"1.0.0","Id":"5ca169f7-9e7b-4861-abf5-859cdb468f6e","ZtdId":"dfb0527f-64d1-4f78-85ff-50cd6fab7e6c","PKID":"","SerialNumber":"","SequenceBlockNumber":1,"TotalBlocks":1}

问题现状 #

• 从CollectionView页面跳转同一「设备详情页」完全正常
• 把参数传到空白页或关于页，页面也能正常加载
• 加了大量Console.WriteLine能显示要加载的设备所有字段，但详情页就是黑屏
• 已经尝试过官方导航传参相关方案及网上多种代码组合，还加了「若SerialNumber为空则关联数据」的逻辑，问题依旧

相关代码 #

扫描页面代码 #

async void BarcodesDetected(object sender, BarcodeDetectionEventArgs e)
{
    try
    {
        var first = e.Results?.FirstOrDefault();
        if (first is not null)
        {
            Dispatcher.Dispatch(() =>
            {
                barcodeGenerator.ClearValue(BarcodeGeneratorView.ValueProperty);
                barcodeGenerator.Format = first.Format;
                barcodeGenerator.Value = first.Value;
            });
        }
        string Json = JToken.Parse(e.Results[0].Value).ToString();
        Models.Device device = JsonConvert.DeserializeObject<Models.Device>(Json);
        var navigationParameters = new Dictionary<string, object>
        {
            { "Device", device }
        };
        await Shell.Current.GoToAsync($"devicedetails", navigationParameters);
    }
    catch (Exception)
    {

    }
}

设备详情页代码 #

public Models.Device Device { get; private set; }

public void ApplyQueryAttributes(IDictionary<string, object> query)
{
    Device = query["Device"] as Models.Device;
    if(String.IsNullOrEmpty(Device.SerialNumber))
    {
        Models.Device device = DeviceData.Devices.FirstOrDefault(a => a.ZtdId == Device.ZtdId);
        Device = device;
    }
    OnPropertyChanged("Device");
}

设备数据示例 #

public static IList<Models.Device> Devices { get; private set; }

static DeviceData()
{
    Devices = new List<Models.Device>
    {
        new Models.Device
        {
            SerialNumber = "00-000001",
            Manufacturer = "Dell, Inc.",
            Model = "XPS 13 9360",
            PurchaseOrderNumber = "",
            GroupTag = "US-EST-001",
            DeploymentProfile = "Hybrid AAD",
            AddressableUserName = "Jane Doe",
            UserPrincipalName = "janedoe@contoso.com",
            ZtdId = "dfb0527f-64d1-4f78-85ff-50cd6fab7e6c",
            AzureActiveDirectoryDeviceId = Guid.NewGuid().ToString(),
            ManagedDeviceId = Guid.NewGuid().ToString()
        }
    };
}

排查方向及解决方案 #

1. 修复空引用风险
   直接用query["Device"]会因为参数缺失报错，先做存在性判断：

   if (query.TryGetValue("Device", out var deviceObj) && deviceObj is Models.Device tempDevice)
   {
       Device = tempDevice;
   }
   else
   {
       await Shell.Current.GoToAsync("..");
       return;
   }
   

2. 处理数据匹配空值
   FirstOrDefault找不到匹配项会返回null，此时Device为空导致UI黑屏，加空值判断：

   if(String.IsNullOrEmpty(Device.SerialNumber))
   {
       Models.Device device = DeviceData.Devices.FirstOrDefault(a => a.ZtdId == Device.ZtdId);
       if(device != null)
       {
           Device = device;
       }
       else
       {
           // 可添加无数据提示或返回逻辑
       }
   }
   

3. 确认UI绑定上下文
   检查详情页XAML的BindingContext是否正确指向ViewModel，且绑定表达式（如{Binding Device.SerialNumber}）无错误；确保ViewModel正确实现了INotifyPropertyChanged接口，OnPropertyChanged调用无误。

4. 确保导航在UI线程执行
   扫描回调可能不在UI线程，导航操作也需调度到UI线程：

   await Dispatcher.DispatchAsync(async () =>
   {
       await Shell.Current.GoToAsync($"devicedetails", navigationParameters);
   });
   

5. 补全异常捕获日志
   空try-catch会隐藏错误，添加日志便于排查：

   catch (Exception ex)
   {
       Console.WriteLine($"导航错误：{ex.Message}\n{ex.StackTrace}");
   }
   

内容的提问来源于stack exchange，提问作者mrhls2312